1. Field of the Invention
The present invention relates to joystick input devices used as controllers for automotive electrical systems or the like. In particular, the present invention relates to means for providing an operational feel of moving in parallel with a panel surface to a user through a tilt-operation knob.
2. Description of the Related Art
Joystick input devices having tiltable components, tilt-operation knobs for operating the tiltable components in a tilt direction, and means for detecting the tilt direction and serving as controllers for automotive electrical systems, such as a car navigation system, or a car audio system, have been known.
FIG. 13 is a cross-sectional view of one such known joystick input device. This joystick input device includes: a casing 101 consisting of an upper casing unit 101a and a lower casing unit 101b; a wiring board 102 held in the casing 101; a flexible sheet 103 attached to the wiring board 102 and having dome portions 103a; tilt-operation sheet switches 104 (tilt-detecting means), a push-button sheet switch 105, and rotating-operation sheet switches 106, each having a fixed contact (not shown) formed on the surface of the wiring board 102 and a conductive material body (not shown) formed on the top of each of the dome portions 103a; an X-Y operating unit 107 supported by the upper casing unit 101a so as to be freely tiltable and arranged such that the lower edge of the X-Y operating unit 107 is opposed to the tilt-operation sheet switches 104; a shaft (a tiltable component) 108 for a tilt operation and a slide operation supported by the X-Y operating unit 107 so as to be freely slidable and arranged such that the lower edge of the shaft 108 is opposed to the push-button sheet switch 105; an operation component (a tilt-operation knob) 109 for both a tilt operation and a push operation integrated with the upper edge of the shaft 108; a spring 110 stretched between the upper casing unit 101a and the shaft 108; a turning knob 111 supported by the upper casing unit 101a so as to be freely turnable; and a turn-operation unit 112 connected to the turning knob 111 and opposed to the rotating-operation sheet switches 106 (see, for example, Japanese Unexamined Utility Model Registration Application Publication No. 7-30431).
In this known joystick input device, when a force is applied on the shaft 108 laterally, the shaft 108 and the X-Y operating unit 107 are tilted in the direction of the force while resisting an elastic force of the spring 110. In accordance with the direction of the force, a required dome portion 103a is then selectively compressed by the end of the X-Y operating unit 107, and at least one or two of the tilt-operation sheet switches 104 are selectively switched to conduction. When a force is applied on the shaft 108 in the axial direction, the shaft 108 is slid in the X-Y operating unit 107 while resisting an elastic force of the spring 110. Another dome portion 103a is then compressed by the end of the shaft 108, and the push-button sheet switch 105 is selectively switched to conduction. When a force is applied on the turning knob 111 in a direction of rotation, the turning knob 111 and the turn-operation unit 112 are turned in the direction of the force. An operational element 112a of the turn-operation unit 112 comes into contact with a side of a required dome portion 103a, and therefore, the required dome portion 103a is tilted, so that the rotating-operation sheet switches 106 are selectively switched to conduction.
As a result, systems can be controlled by the use of contact signals supplied from one or two of the tilt-operation sheet switches 104, from the push-button sheet switch 105, and from the rotating-operation sheet switches 106.
When this type of a joystick input device is used as a controller for an automotive electrical system, a driver must operate the operation component 109 or the turning knob 111 without having to stop looking ahead while driving the car, and therefore, it is highly necessary that the joystick input device have ease of use to reliably avoid an operating error.
However, the above-described known joystick input device has no means for regulating a tilt operation of the shaft 108 or means for regulating a slide operation thereof, and therefore, both operations of the shaft 108 can be carried out simultaneously. As a result, for example, in a case where a cursor movement on a display unit in a car navigation system is controlled based on a contact signal supplied from the tilt-operation sheet switches 104 upon a tilt operation of the shaft 108 and a selection from menu buttons appearing on the display unit in the car navigation system is controlled based on a contact signal supplied from the push-button sheet switch 105 upon a slide operation of the shaft 108, a slide operation is prone to interrupt a tilt-operation process or, in contrast, a tilt operation is prone to interrupt a slide-operation process. Therefore, there is a problem in that it is difficult to reliably select a desired menu button without having to look at the input device.
In order to enhance the upscale image in a car having this type of a joystick input device, it may be desired that, when the tilt-operation knob is tilted in the tilt direction of the tiltable component, the feel of moving in parallel with a surface of a panel to which the joystick input device is mounted be provided to a user through the tilt-operation knob, not that the direct feel of tilt of the tiltable component be provided to a user through the tilt-operation knob.
A structure in which the feel of parallel movement is provided to a user through the tilt-operation knob can be achieved by the provision of means for guiding the tilt-operation knob in the direction parallel to the panel and means for conveying an operation force of the tilt-operation knob to the tiltable component between the tilt-operation knob and the tiltable component. However, this process complicates the entire structure, and therefore, increases the cost of the joystick input device. As a result, this process is not realized in practice. If the length of the tiltable component is increased, the tilt-operation knob can have a pseudo-feel of parallel movement. However, in a known joystick input device, the lower casing unit 101b is mounted on a panel P, as described in FIG. 13. Therefore, if the length of the shaft (tiltable component) 108 is increased, the operation component (tilt-operation knob) 109 protrudes significantly in the cabin of the car, and this has adverse effects on the look of the car's interior and on the safety. For this reason, enlargement of the length of the shaft (tiltable component) 108 is limited and it is difficult to provide the operation component (tilt-operation knob) 109 with a good operational feel of parallel movement.